The goal of this experiment was to carry out a multiple-step synthesis reaction in order to develop a benzyl ether derivative. This was done by reduction the aldehyde to create an alcohol and then performing an etherification reaction by adding another alcohol. These reactions have major importance because of the variety of the derivatives that can be created from a single aldehyde, a science called organoleptic chemistry. Major procedural techniques were reflux, funnel separation, and rotary evaporation. Reflux is a technique that accelerates and maximizes the efficiency of a chemical reaction by stirring and heating a solution. Funnel separation is a purification technique that allows for the organic layer of a solution to be removed from the aqueous layer after a reaction, this will remove some of the solvents or reagents and what doesn’t get removed will be in rotary evaporation. Rotary evaporation removes the solvent from the solution which then solidifies the desired product. Major analysis techniques were IR, NMR, and TLC in this lab. IR spectroscopy exposes the organic molecules to infrared radiation and based on the energy given off by the vibrations of the bonds in the molecule, absorption occurs and an IR spectrum can be given. NMR calculates the energy of protons based off aligning and opposing spins caused by a magnetic field. TLC uses a solvent that carries the pieces of a spot up a plate based on the polarities of its components. The major purification technique utilized in this lab was column chromatography. It is similar to TLC in that an eluent carries components of a solution through a stationary phase, but in column chromatography the components are able to be separated and therefore isolated into pure products.

To start the multi-step synthesis, the aldehyde was reduced to an alcohol. This was done by utilizing the reducing agent, NaBH4, to decrease the number of oxygen bonds from 4 to 3 and then the addition of acid allowed for the increase of hydrogen bonds to form the alcohol. This process was then purified by using separatory techniques. Ethyl acetate was used to dissolve the solids, so the organic

layer was on top when the separatory funnel was settled. Once the organic layer had been washed a rotary evaporator was used in order to evaporate impurities and change the liquid intermediate into solid intermediate. Here, 1.029 g of the intermediate (piperonyl alcohol) was created. A possible error in the yield could have been from not allowing the reaction to go to completion after the addition of NaBH4. IR and NMR spectroscopy was used in order to determine the purity of the intermediate. IR spectroscopy showed a peak at 2986.82 cm-1 which correlated to a C-H bond which should be expected in any organic molecule, but the peaks that were specifically consistent with its structure were at 1490.07 cm-1, 1275.61 cm-1, and 810.03 cm-1. These peaks correlated to a C=C aromatic bond, C-O alcohol bond, and C-H aromatic bond. Even though most of these peaks were weak in strength, they were necessary in determining the structure. There were some peaks missing in accordance to the structure, so the intermediate wasn’t all that pure. This could be a possible error in yield and purity going on with Parts 2 and 3 in the experiment. The NMR was a little cluttered, but a ratio on the integration was found in order to get better results. There were 6 main peaks, 3 of which that fell in the aromatic region (6.5 – 8 ppm) and 1, at 2.03 ppm, corresponded to the hydrogen on the alcohol group. The assignments, therefore, were easily justified and although the NMR seemed to have extraneous peaks, the data reported was fairly accurate.

In Part 2, 0.743 g of piperonyl alcohol was used in the acid-catalyzed etherification reaction. The reaction was refluxed until all of the starting material had been converted into product. This was monitored by TLC analysis; 3 spots were made for these analyses, the first was of the starting material, second was a combination of the starting material and the refluxed solution, and the third was solely the refluxed solution. The reaction was deemed complete when the analysis showed that the product was isolated without starting material and this was confirmed when TLC had one mark on the third spot that was higher up the plate than the starting material. More separation techniques were utilized to further purify the product and a rotary evaporator removed the solvent from the product.

The next step was to purify the product and this was done by column chromatography and TLC analysis. The eluent wasn’t given in this step; so in order to find a sufficient eluent, TLCs were run until the product had an Rf value of 0.3. This Rf value was found having a solvent in a 6:1 hexane to ethyl acetate ratio. This solvent was used as the mobile phase in the column chromatography and only pure fractions with an Rf value around 0.3 were transferred to a flask for rotary evaporation. Fractions 7-9 were found to be the purest and after rotary evaporation, 0.243 g of product was made. This amount is barely a quarter of the theoretical yield (27.61%), which suggested that errors were made during column chromatography. One such error could have been having too large of fractions; this would cause some of the either starting material or other reagents to run-off into the pure compound fractions. On the TLC analysis it would show up as impure even though there is some compound in it which would create less yield. Once the solid was collect IR and NMR samples were prepared and analyzed. The IR was accurate and had all significant bond types including both aromatic and aliphatic C-O ether bonds. This was a crucial difference in the product compared to the intermediate’s IR. They both had aromatic peaks, but the ether in the product was a major difference in determining the purity of the product. The IR again was a little cluttered, but during the analysis, 7 different protons were able to be found. The extra proton came from the ethanol reacting with piperonyl alcohol to get an ethyl chain as a part of the ether. These protons on the chain were easily spotted because of the multiplicity. All the aromatic protons a part of the piperonyl chain were either singlets or doublets, and the ethyl chain had a quartet and triplet. The integration again had to be reduced by a factor in order to get the correct numbers. Although the yield was relatively low, the NMR was fairly accurate. The product and intermediate also had the 3 different protons in the aromatic region (6.5-8 ppm) in both NMR which is accurate with the structure and then another proton at around 5.9 ppm for both which correlated to the set in the ring at the very bottom of the molecule.